From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user pointers, v1 and v2, and swaps the words they point to in hand-written assembly. l.lwz r29,0(r4) l.lwz r27,0(r5) l.sw 0(r4),r27 l.sw 0(r5),r29 The pointers are not checked with access_ok(). The four memory accesses also have no exception table entries. A caller passes a kernel address as either pointer, and the syscall reads from and writes to it directly. This gives an unprivileged process a kernel read/write primitive. It overwrites kernel data such as the sys_call_table, gaining code execution in kernel context. Check both pointers before entering the critical section. Add fixups for the four memory accesses so faults on valid but unmapped user addresses return -EFAULT. [shorne@gmail.com: fix comment style] Fixes: 9d02a4283e9c ("OpenRISC: Boot code") Cc: stable@vger.kernel.org Signed-off-by: Ali Ahmet Memis Signed-off-by: Stafford Horne --- fs/nilfs2/direct.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 fs/nilfs2/direct.h (limited to 'fs/nilfs2/direct.h') diff --git a/fs/nilfs2/direct.h b/fs/nilfs2/direct.h new file mode 100644 index 000000000..b7ca89626 --- /dev/null +++ b/fs/nilfs2/direct.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * NILFS direct block pointer. + * + * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation. + * + * Written by Koji Sato. + */ + +#ifndef _NILFS_DIRECT_H +#define _NILFS_DIRECT_H + +#include +#include +#include "bmap.h" + + +#define NILFS_DIRECT_NBLOCKS (NILFS_BMAP_SIZE / sizeof(__le64) - 1) +#define NILFS_DIRECT_KEY_MIN 0 +#define NILFS_DIRECT_KEY_MAX (NILFS_DIRECT_NBLOCKS - 1) + + +int nilfs_direct_init(struct nilfs_bmap *); +int nilfs_direct_delete_and_convert(struct nilfs_bmap *, __u64, __u64 *, + __u64 *, int); + + +#endif /* _NILFS_DIRECT_H */ -- cgit v1.3.1